Why were american suburbs of the 1950s so heavily segregated?

This is on the grounds that inhabitants intermediaries and real estate agents managed in contracts and home loans the banned the offer of the nonwhite home. In the 1950s, the suburbs have noticeably increased to 47% and more people have become the owner of a small territory. 

Cherokee  removal, part of the trail of tears, refers to the  forced  relocation between 1836 and 1839 of thecherokee  nation from  their lands ingeorgia, south carolina, north carolina, tennessee, texas, and alabama to the indian territory (present day oklahoma)  in  the thenwestern united states, and the resultant deaths

The answer b is correct this all occurred during the red scare